1. (Field of the Invention)
The present invention relates to an automotive rolling machine and, more particularly, to an automotive rolling machine which is designed to pave a large flat ground-surface such as that of a tennis court, and which has lengthy rollers that are improved in respect to their steerability.
2. (Description of the Prior Art)
A conventional automotive rolling machine for use on pavement is constructed such that it has rollers at the front and back portions of its machine body. Such a prior art machine is an exclusive rolling machine used for pavement of a large flat ground-surface such as that of a tennis court, and is desired such that it has lengthy rollers which extend in the longitudinal direction of its machine body.
The above-mentioned conventional automotive rolling machine is used in a manner so that its machine body is laterally advanced, since the rollers extend in the longitudinal direction of the machine body and are parallel to each other. It has, however, no steering means while, on the other hand, the ground has no completely uniform horizontal surface. For this reason, it has a drawback that, when it makes its rolling run, its running is affected by the irregularities of the ground surface, thus causing the machine to fail by making it turn leftwards or rightwards.
Conventionally, therefore, in order to prevent the machine from moving in such a curvilinear manner, a bulky article is purposely placed on the ground. By causing one end of the roller to ride over the bulky article, the end portion thereof is less rotated, thereby adjusting the advancing direction of the machine.
However, where such a bulky article is disposed, the opposite end of the roller is temporarily stopped from advancing, whereby the rolling effect becomes excessive at the corresponding ground surface. For this reason, the paved surface often became locally irregular, failing to have complete flatness.
Further, the automotive rolling machine is heavy in weight, and it is therefore extremely difficult to adjust the direction of advance of the machine. For the reason there is a high risk associated with a manual disposition of the bulky article beneath the roller. Thus, efficiency of the conventional machines were greatly reduced by irregular surfaces.
In order to solve the above-mentioned problem, the applicant of the present application previously proposed an automotive paving roller machine having its rollers equipped with a steering means as disclosed in Japanese Utility Model Application Disclosure No. 203708/84.
In this steering means, however, when one of the two parallel rollers is used for changing the advancing direction, its movement varies from a parallel posture to a V-shaped posture as taken in comparison with the other roller. In this case, the directing roller revolves less at the base end portion then it revolves at the tip end portion. That is, when the advancing direction is changed, a difference is produced between the rolling effect of the former and that of the latter. Further, it is difficult to alter the advancing direction at the time of going backwards although it is possible to alter at the time of going forwards.